Study of Roodgaz clay mineral deposit
|Category||Economic geology & mineral exploration|
|Location||The 25 Symposium of Geosciences|
|Author||M.Razi Arbabi - Dr. B.Etemadi|
|Holding Date||30 June 2007|
Roodgaz clay mineral deposit is located at 50 km to the west of Tabas city in the Yazd province and located between lower limestone, sandy limestone and upper thin-bedded shale of Badamoo formation with Jurasic age. The sedimentary formations of the deposit is evident.Clay layers associate with shale-limy sediments of badamoo formation seem to be deposited a grabon sedimentary basin.Then, middle-simerian orogeny movements has affected this basin. On the basis of mineralogical results; quartz and illite/moscuvite are the main minerals and pyrophillite, natroalunite, natrojarosite, jarosite, hematite and gypsum are accessory minerals.Pyrophillite and illite have formed during weathering of parent rocks that rich in the silica and the gypsum and alunite group minerals have formed latter.Geochemical studies are indicate the during weathering processes, the earthy alkali and alkali elements are depleted, and silica and alumin are enriched.The survey of weathering diagram and calculation of chemical index of alteration (CIA) and chemical index of weathering (CIW) has indicated of relatively intense weathering of sediment source rocks. The enrichment of ions such as Cs, Ba, Rb, K and V are due to illite adsorption, and the Y, Zr, Nb and transition elements are depleted.The normalized pattern of rare earth elements with the chondrite underlied the enrichment of LREEE/HREE, with negative anomaly of Eu and positive slightly anomaly of Ce.The patterns also is favours of relatively intense weathering of source acidic rocks, and also imobile elements such as La, Th, Sc shows the granite or granodiorite composition of source rock.